Hydrogels and method of making the same

Abstract

The present disclosure relates to hydrogels and their use for repairing or supplementing body tissue. The hydrogels are capable of safe injection into patients through fine gauge needles and are suitable for repairing, supplementing, or replacing the nucleus pulposus of an intervertebral disc. Methods of manufacturing and methods of using the hydrogels of the present disclosure to repair or replace tissues are also disclosed.

The invention claimed is: 
     
       1. A method of repairing or supplementing a tissue in a patient in need thereof, comprising:
 (a) melting a hydrogel in a container, wherein the hydrogel comprises:
 about 12 wt. % to about 22 wt. % of polyvinyl alcohol; 
 about 0.12 wt. % to about 0.22 wt. % of polyvinylpyrrolidone; and 
 about 12 wt. % to about 22 wt. % of non-functionalized polyethylene glycol having a Mw of about 800 Da to about 2,000 Da, wherein the hydrogel does not contain a chemically crosslinked polymer; and 
 a solvent; 
 and 
 
 (b) injecting a therapeutically effective amount of the melted hydrogel, wherein the hydrogel does not contain a chemically cross-linked polymer, through a 15 gauge or smaller needle into the tissue in need of repair or supplement to provide a tissue implant. 
 
     
     
       2. The method of  claim 1 , wherein the tissue is the nucleus of an intervertebral disc. 
     
     
       3. The method of  claim 2 , further comprising injecting an enzyme into the nucleus of the intervertebral disc to dissolve the nucleus pulposus before injecting the melted hydrogel. 
     
     
       4. The method of  claim 2 , wherein the method further comprises determining the therapeutically effective amount of the melted hydrogel by observing the implant in real time as it the melted hydrogel is injected using radiographic imaging. 
     
     
       5. The method of  claim 2 , wherein the method further comprises determining the therapeutically effective amount of the melted hydrogel by:
 (a) injecting the melted hydrogel to achieve a pressure of about 120 psi to about 200 psi as determined by a pressure gauge on a delivery system; 
 (b) pausing the melted hydrogel injection; 
 (c) monitoring the pressure gauge for a pressure decrease below 120 psi to about 200 psi; 
 (d) injecting additional melted hydrogel until 120 psi to about 200 psi is achieved; and 
 (e) repeating the steps (b)-(d) until the pressure decrease is less than about 10% of 120 psi to about 200 psi. 
 
     
     
       6. A kit for disc augmentation, comprising:
 about 1 cc to about 6 cc of a hydrogel packaged in a suitable container, 
 wherein the hydrogel comprises:
 about 12 wt. % to about 22 wt. % of polyvinyl alcohol; 
 about 0.12 wt. % to about 0.22 wt. % of polyvinylpyrrolidone; 
 about 12 wt. % to about 22 wt. % of non-functionalized polyethylene glycol having a Mw of about 800 Da to about 2,000 Da, wherein the injectable form of the hydrogel does not contain a chemically crosslinked polymer 
 and the injectable form of the hydrogel is injectable at about 65° C. through a 15-gauge needle into the nucleus of a human patient's intervertebral disc. 
 
 
     
     
       7. The kit of  claim 6 , wherein the non-functionalized polyethylene glycol has an Mw of about 800 Da to about 1,200 Da. 
     
     
       8. The kit of  claim 6 , wherein the hydrogel further comprises a contrast agent. 
     
     
       9. The kit of  claim 8 , wherein the contrast agent is barium sulfate. 
     
     
       10. The kit of  claim 8 , wherein the hydrogel comprises about 9 wt. % to about 19 wt. % of the contrast agent. 
     
     
       11. The kit of  claim 6 , wherein the polyvinyl alcohol has a Mw of about 135,000 Da to about 155,000 Da. 
     
     
       12. The kit of  claim 6 , wherein the polyvinylpyrrolidone has a Mw of about 35,000 Da to about 55,000 Da. 
     
     
       13. The kit of  claim 6 , further comprising a hydrogel delivery system, wherein the hydrogel delivery system comprises a syringe assembly. 
     
     
       14. The kit of  claim 13 , wherein the syringe assembly comprises a heater assembly. 
     
     
       15. The kit of  claim 6 , wherein the suitable container is a syringe.